Ovens having linear sources of visible and infrared radiant energy are disclosed and described in U.S. Pat. No. 5,036,179 and U.S. patent application Ser. No. 07/738,207 which are incorporated herein by reference. These ovens provide high-speed, high-quality cooking and baking of food items by impinging high-intensity visible, near-visible, and infrared radiations onto a food item. The ovens cook the food items within the short periods of time normally found in microwave cooking while maintaining the browning of infrared cooking and the quality of conduction-convection cooking. When food is exposed to a sufficiently intense source of visible, near-visible, and infrared radiation, the food absorbs low levels of visible and near-visible radiation, thereby allowing the energy to penetrate the foodstuff and heat it deeply. The longer infrared radiation does not penetrate deeply but acts as an effective browning agent.
Ordinarily, the source of the visible, near-visible and infrared radiation used with the present invention is in excess of two quartz-halogen tungsten lamps, or equivalent means such as quartz arc lamps. Typical quartz-halogen lamps of this type operate at 3000 degrees Kelvin and convert electrical energy into black body radiation having a range of wavelengths from 0.4 .mu.m to 4.5 .mu.m with a peak intensity at 0.965 .mu.m. Each lamp can generally provide about 2 KW of radiant energy with a significant portion of the energy in the visible light spectrum.
The ovens can use a plurality of these lamp or an array of several lamps either operated in unison or selectively operated in varying combinations as necessary for the particular food item sought to be cooked. These radiation sources are ordinarily positioned above and below the food item. The walls of the surrounding food chamber are preferably made from highly reflective surfaces. The visible and infrared waves from the radiation sources impinge directly on the food item and are also reflected off the reflected surfaces and onto the food item from many angles. This reflecting action improves uniformity of cooking. The speed of cooking makes it possible to monitor the cooking process and select the precise instant to terminate the cooking process.
The cooking energy applied and the cooking speed of these ovens makes it critical to cook the food item the appropriate length of time to achieve the desired degree of cooking because in a short period of cooking time the food item can go from undercooked to overcooked condition.